I think Kareem has the greatest career/most achievements.
I think LeBron is the best basketball player of all time.
I think Jordan is considered the GOAT for being second in both of those categories and being the perfect figure at the perfect time. If Michael Jordan has the exact same career starting in 1974 instead of 84, I don't think we view him the same way. Cable, Sportscenter, Nike, Gatorade, and the NBA that Magic and Bird helped build first gave him the chance to build the status he has.
Not to mention, the sports conversation is/has been dominated by the age group who worship him and somehow consider his superiority emblematic of the legitimacy of their entire era. I think as time passes and those folks are replaced by people who grew up with LeBron, you'll see a shift.